Test: Code Generation & Optimization- 2

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This mock test of Test: Code Generation & Optimization- 2 for Computer Science Engineering (CSE) helps you for every Computer Science Engineering (CSE) entrance exam. This contains 15 Multiple Choice Questions for Computer Science Engineering (CSE) Test: Code Generation & Optimization- 2 (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Code Generation & Optimization- 2 quiz give you a good mix of easy questions and tough questions. Computer Science Engineering (CSE) students definitely take this Test: Code Generation & Optimization- 2 exercise for a better result in the exam. You can find other Test: Code Generation & Optimization- 2 extra questions, long questions & short questions for Computer Science Engineering (CSE) on EduRev as well by searching above.

QUESTION: 1

In some phase of compiler

Input
temp1 := Inttoreal (60)
temp2 := id3 * temp1
temp3 := id2 + temp2
id1 := temp3
Output
temp 1 := id3 * 60.0
id1 := id2 + temp1

where temp 1 , temp 2 , temp 3 are temporary storage, id1, id2, Id3 are identifier into real is converting int 60 to real number. The above phase is

A.
Code optimizer
B.
Code generator
C.
intermediate code generator
D.
None of the above

Solution:

Input:
temp1: = inttoreal(60)
temp2: = id3*temp1
temp3 : = id2 + temp2
id1 : = temp3

Output:
temp1 : = id3*60.0
id1 : id2 + temp1

The above phase is code optimization, because it is optimizing the intermediate code using only storages as temp 1 and id1.

QUESTION: 2

The DAG shown here represents

A.
a + (b*c) - d
B.
a + b *c *b *c -d
C.
(a + b)*(c- d)
D.
(a + b*c)*(b*c- d)

Solution:

The above DAG represents
(a + b * C ) * { b * C - d )

QUESTION: 3

Any Directed Acyclic Graph must have

A.
Atleast one vertex with indegree 1 and atleast one vertex with outdegree 0.
B.
Atleast one vertex with indegree 0 or atleast one vertex with outdegree 0,
C.
Atleast one vertex with indegree 0 and atleast one vertex with outdegree 0,
D.
Atleast one vertex with indegree 0 and atleast one vertex with outdegree 1

Solution:

Simplest DAG:

QUESTION: 4

The DAG shown here represents:

A.
(a - b) * (a + b) + (c + d) * (c + d)
B.
(a - b) * (c + d) + (a - b) * (c - d)
C.
(a * b) + (c * d) * (a * b) + ( c * d)
D.
(a + b) * ( c + d) + (a - b) * (c + d)

Solution:

Simplifying the DAG:

Thus result: (a + b) * (c + cf) + (a - b) * (c + d)

QUESTION: 5

Consider the DAG with V = {1, 2, 3, 4, 5, 6}, shown below

Which of the following is NOT a topological ordering

A.
1 2 3 4 5 6
B.
1 3 2 4 5 6
C.
1 3 2 4 6 5
D.
3 2 4 1 6 5

Solution:

QUESTION: 6

A directed acyclic graph represents one form of intermediate representation. The number of non terminals nodes in DAG of a = (b + c)*(b + c) expression is

A.
2
B.
3
C.
4
D.
5

Solution:

Since indegree of node 3 is 1. So cannot start topological ordering with node 3 only start node will be 1.

QUESTION: 7

A pictorial representation of the value computed by each statement in the basic block is

A.
Tree
B.
DAG
C.
Graph
D.
None of these

Solution:

A pictorial representation of the value computed by. each statement in the basic block is control flow graph.

QUESTION: 8

DAG representation of a basic block allows

A.
Automatic detection of local common sub-expressions.
B.
Automatic detection of induction variables.
C.
Automatic detection of loop invariant.
D.
None of the above

Solution:

DAG representation of a basic block allows automatic detection of local common sub expression.

QUESTION: 9

The intermediate code generated for the following syntax tree is:

A.
iac + cdb + - +
B.
iacb + cd uminus * - +
C.
iacb + cd * - +
D.
None of the above

Solution:

The intermediate code generated is iacb + cd uminus * - +

QUESTION: 10

The triple representation for following representation is:

A.
B.
C.
D.
None of the above

Solution:

QUESTION: 11

Generation of intermediate code based on an abstract machine model is useful in compilers because

A.
It makes implementation of lexical analysis and syntax analysis easier.
B.
Syntax-directed translations can be written for intermediate code generation.
C.
It enhances the portability of the front end of the compiler.
D.
It is not possible to generate code for real machines directly from high level language programs

Solution:

Intermediate code enhance the portability of the front end of the compiler.

QUESTION: 12

Three address code’ technique for intermediate code generation shows that each statement usually contains three addresses. Three addresses are as follows:

A.
Two addresses for operands, one for operator
B.
One for all operator, one for all operands and one for result
C.
One for result, two for operands
D.
None of the above

Solution:

Three address code formate is two addresses for operands and one for operator.

QUESTION: 13

Consider the following arithmetic infix expression Q.

Transform 'Q' into its equivalent postfix expression.

A.
B.
C.
D.
None of the above

Solution:

Given expression

Equivalent postfix expression;

QUESTION: 14

Which of the following is not a type of three address statements?

A.
Copy statements
B.
Index assignment statements
C.
Pointer assignments
D.
None of the above

Solution:

QUESTION: 15

Consider the following statements:
S₁: Three address code is a linearized representation of a syntax tree.
S₂: The syntax tree not depicts the natural hierarchical structure of source program

Which of the above statements is/are true